Nanoindentation as a strength probe—a study on the hardness dependence of indent size for fine-grained and coarse-grained ferritic steel

A nanoindentation hardness testing system, including an atomic-force microscope (AFM)-based nanoindentation tester and a calibration method using electrolytically polished single-crystal metals as references, was proposed. This was applied to a study of the mechanical properties of fine-grained ferritic steel (grain size of 1.2 μm) and coarse-grained ferritic steel (30 μm). An empirical function giving the macroscopic hardness for all four reference metals from the nanoindentation force curves was established. The converted Vickers hardness (HV*) of the coarse-grained steel is almost independent of the indent size. The fine-grained steel shows only HV* 130 with an indent of only 100 nm, compared with a macroscopic hardness of HV 210. The difference, HV 80, is considered to reflect the amount of grain-boundary strengthening. The critical indent size for the hardness transition seems to be around 1 μm, comparable to the grain size of the specimen. This result supports the explanation of grainboundary strengthening. It is also consistent with Pickering’s work on low-carbon steel, as the estimated locking parameter (k of 2.6×10⁵ N/m^3/2) in the Hall-Petch relationship is in good agreement with his value of 2.4×10⁵ N/m^3/2.     

Urinary leukotriene E4 and 11-dehydrothromboxane B2 in patients with aspirin-sensitive asthma

The objective of this study was to define the participation of cysteinyl leukotrienes (LTs) or thromboxane A2 in the pathogenesis of aspirin-sensitive asthma (ASA). Leukotriene E4 (LTE4) and 11-dehydrothromboxane B2 (11DTXB2) values in spot urine were measured in 22 asthmatics with a history of aspirin sensitivity and in 17 without such a history (non-aspirin-sensitive asthma [NASA]) in the outpatient clinic. The urinary LTE4 value was significantly higher in ASA patients than in NASA (340 +/- 47 vs 65 +/- 15 pg/mg.cr, P < 0.001), but there was no significant difference in urinary 11DTXB2 between the two groups (891 +/- 77 vs 657 +/- 90 pg/mg.cr). A high value of LTE4 was not associated with type of asthma, severity of disease, oral prednisolone treatment, sex, or age. A higher value of 11DTXB2 was observed in the atopic type than the nonatopic type in ASA (1086 +/- 111 vs 697 +/- 147 pg/mg.cr, P < 0.05). No correlation was observed between urinary LTE4 and 11DTXB2 in either ASA or NASA. In conclusion, LTs may play an important role in the pathogenesis of ASA, and TXA2 in the pathogenesis of the atopic type in ASA.     

Facile one-step route to polyaniline–silver nanocomposite particles and their application as a colored particulate emulsifier

Polyaniline–silver nanocomposites were synthesized in the form of colloidal particles by the facile one-step aqueous chemical oxidative dispersion polymerization of aniline using silver nitrate as an oxidant and poly(vinyl alcohol) as a colloidal stabilizer. Aniline monomer was oxidized by silver ions, yielding polyaniline and elemental Ag simultaneously. The synthesized nanocomposite particles were colloidally stable over 2 years and transmission electron microscopy studies indicated the production of spherical, plate and rod-shaped polyaniline–silver nanocomposite particles with a silver core–polyaniline shell morphology. The conductivity of a pressed pellet of the nanocomposite particles using the conventional four-point probe technique was 1.4 × 10^?2 S/cm at 25 °C. The nanocomposite particles behaved as a ‘colored’ particulate emulsifier for the stabilization of transparent oil-in-water emulsions.     

The effect of write current on thermal flying height control sliders with dual heater/insulator elements

The effect of write induced pole tip protrusion on the magnetic spacing of the head/disk interface has to be taken into consideration as flying heights approach the spacing regime of a few nano-meters. Thermal flying height control (TFC) sliders are presently in common use in hard disk drives to control the flying height at the read/write element during drive operations. In this paper the flying characteristics of TFC sliders with dual heater/insulator elements are investigated. Simulation results are shown for situations where the write current is ??on?? and where the write current is ??off??. The effect of design parameters of two heater/insulator elements is studied to optimize the performance of TFC slider.     

Changes in symptom and thermography images after lumbar sympathetic ganglion block

In 35 lower limbs of 22 patients with peripheral circulation disturbance, we evaluated the effects of lumbar sympathetic ganglion block (LSGB) by skin temperature difference (delta T) between the two measured by thermography before and after LSGB. We divided the patients into two groups; ASO group (n = 15): patients with chronic arterial occulusive diseases, and nonASO group (n = 7): those with peripheral circulation disturbance partly due to decrease nervous function. After LSGB, we recognized a significant increase in delta T and remission of ischemic symptoms in all the patients of nonASO group and those in early stage of ASO group. This suggests that in ASO group LSGB should be applied as soon as possible to obtain good outcome, and thermography is useful to evaluate the effects of LSGB in patients with peripheral circulation disturbance of the lower limbs.     

EFFECTS OF HEXASULFOBUTYLATED C60 ON THE GASTRIC CIRCULAR MUSCLE OF GUINEA PIG

The effects of hexasulfobutylated (FC₄S), the fullerene derivative on the contraction of smooth muscle were tested pharmacologically on the circular muscle of stomach of guinea pigs. The effects of monomalonic acid C₆₀ (MMA C₆₀) on the same preparations were compared. The effects of those compounds on the taenia coli, portal vein and vas deferens of guinea pigs were also tested. The FC₄S did, while MMA C₆₀ did not elicit contracture of the circular muscle of stomach and taenia coli. Both FC₄S and MMA C₆₀ did not elicit contraction on the portal vein and on the vas deferens of the guinea pig. Prazosin (0.5 μM) or propranolol (0.5 μM) did not alter the FC₄S elicit contracture of the circular muscle of stomach. However, atropine (0.01, 0.1 and 1 μM), tetrodotoxin (0.1 μM) or low calcium medium decreased reversibly the FC₄S elicited contracture of the circular muscle of stomach. The effect of FC₄S on the contracture of the gastric muscles was also tested using various muscarinic receptor subtype antagonists. 4-DAMP (1 μM), muscarinic M3 receptor antagonist, and tropicamide (1 μM), muscarinic M4 receptor antagonist, did not alter the contracture elicited by FC₄S. Pirenzepine (0.1 μM), muscarinic M1 receptor antagonist, and methoctramine (0.25 μM), muscarinic M2 receptor antagonist, significantly decreased the FC₄S elicited contracture of the circular muscle. Atropine (1 μM) or tetrodotoxin (0.1 μM) completely blocked the FC₄S elicited contracture of the circular muscle of stomach. It is concluded that FC₄S elicited contracture of the circular muscle of stomach. The effect may be due to FC₄S acts on the cholinergic cells existed in the gastric muscle and indirectly activating the tetrodotoxin dependent releasing of the transmitters from the cells, then, activating the muscarinice M1, M2 receptors in the muscle eliciting the contractures.     

Single molecule fluorescence autocorrelation measurement on anisotropic molecular diffusion in nematic liquid crystal

Diffusion kinetics of three dyes in nematic liquid crystals are studied with single-molecule fluorescence autocorrelation spectroscopy. Markedly large anisotropy was observed in the diffusion coefficient and structure of diffusion molecules showed no marked effect on the anisotropy.     

A 0.18-μm 256-Mb DDR-SDRAM with low-cost post-mold tuning methodfor DLL replica

A 200-MHz double-data-rate synchronous-DRAM (DDR-SDRAM) was developed. The chip contains a delay-locked loop (DLL) which performs over a wide range of operating conditions. Post-mold-tuning allows precise replica programming. A 200-MHz intra-chip data bus is suitable for DDR operation     

Poly(dithiafulvene)s containing alkoxy groups and mesogenic moiety in the side chain: synthesis,properties and their charge-transfer complex

Summary Poly(dithiafulvene)s having alkoxy group and mesogenic moiety in the side chain were prepared by cycloaddition polymerization. The effects of the side chains on the structural and optical properties of poly(dithiafulvene)s in solution were investigated. Furthermore, the film state properties of the polymers and their charge transfer complex with electron acceptor were studied before and after annealing.     

Anionic surfactants: lauric products

Lauryl sulfate and lauryl ether sulfate obtained by the sulfation of lauryl alcohol and lauryl alcohol ethoxylate are representative of anionic surfactants and are used as a formable detergent or an emulsifier. For the sulfation of lauryl alcohol and lauryl alcohol ethoxylate, SO₃ gas, it was found that the quality of products was significantly influenced by the reaction conditions. In order to obtain good quality products we developed a new technology by using a new type of reactor called a “climbing film reactor,” in which SO₃ gas and liquid raw material flow ascendingly.